Multistage uranium conversion fluidized bed reactor
By using multi-stage shallow fluidized beds and overflow pipes in the uranium conversion fluidized bed reactor, the problems of unstable fluidization quality, high reaction gas consumption and large equipment vibration are solved, and more efficient Safer uranium conversion fluidized bed reactor performance.
Patent Information
- Application Number
- CN202421097394.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-20
- Publication Date
- 2025-02-21
- Estimated Expiration
- 2034-05-20
AI Technical Summary
The existing uranium conversion fluidized bed reactors have problems such as unstable fluidization quality, high reaction gas consumption, high after-treatment costs and large equipment vibration, which affects the safety and efficiency of the production process.
Using a multi-stage uranium conversion fluidized bed reactor, multiple gas distribution plates are arranged inside the reactor main body, and they are divided into multi-stage shallow fluidized beds, and overflow is set between adjacent two-stage fluidized beds. Flow tube and heat exchange tube bundle to maintain high fluidization quality and control particle remixture and temperature gradient.
It improves the fluidization quality of the fluidized bed, reduces the consumption of reaction gas and after-treatment costs, improves the control level of product quality, and enhances the long-term safety and reliability of the equipment.
Smart Images
Figure CN222510918U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of hydrofluorination or hydrogen reduction process in uranium purification and conversion process, in particular to a multi-stage uranium conversion fluidized bed reactor. Background Art
[0002] Natural uranium conversion refers to the industrial production process of converting uranium oxide into pure uranium hexafluoride required for uranium enrichment. It is a key link in the nuclear fuel production process and one of the basic elements of the nuclear fuel cycle. There are two purification process technology routes for natural uranium conversion: "wet method" (i.e. refined fluorination method) and "dry method" (i.e. fluoride volatilization method). Compared with the "wet" process, the "dry" process has a shorter process flow, uses less chemical reagents and produces less waste liquid in the production process, and has better economic and social benefits. However, it has higher requirements on the quality of raw materials and has the problem of poor adaptability of raw materials.
[0003] At present, my country has no research reserves in the field of fluidized bed reactor technology for hydrogen reduction process in uranium purification and conversion. The hydrofluorination process of the current production line adopts a two-stage countercurrent series fluidized bed reactor. However, in the actual production process, the main problems of this device are:
[0004] (1) Since the reactor uses a relatively high dense phase bed and a relatively low operating gas velocity, it is difficult to maintain the overall fluidization quality of the bed at a high level. Local dead beds and gas short circuits often occur in the bed, which can also cause unstable product quality at the reactor outlet and large equipment vibrations, which can easily lead to safety operation accidents.
[0005] (2) The concentration of the reaction gas in the tail gas at the top of the primary reactor is high, the reaction gas consumption is high, and the treatment cost of the reaction gas tail gas is very high;
[0006] (3) Due to the influence of bed fluidization quality and particle backmixing, it is difficult to control the quality of the final product particles. Utility Model Content
[0007] In order to overcome the problems of difficult product quality control, high reaction gas consumption and high post-processing cost in the prior art uranium conversion fluidized bed reactor, and large equipment vibration affecting long-term safe operation, the utility model provides a multi-stage uranium conversion fluidized bed reactor to improve reactor performance, reduce operating costs and improve the long-term reliability of the equipment. The specific technical solution is as follows:
[0008] A multi-stage uranium conversion fluidized bed reactor comprises a reactor body, wherein the reactor body comprises N-stage fluidized bed layers, N≥2, N is an integer, and from top to bottom are the first-stage fluidized bed layer to the N-stage fluidized bed layer, and the bottoms of the N-stage fluidized bed layers are all provided with gas distribution plates, and the gas distribution plates separate the two adjacent stages of the fluidized bed layers, and an overflow pipe is provided between the two adjacent stages of the fluidized bed layers, and the overflow pipe passes through the gas distribution plate to connect the two adjacent stages of the fluidized bed layers.
[0009] Several gas distribution plates are arranged inside the reactor body, and the several gas distribution plates divide the inside of the reactor body from top to bottom into N-level fluidized bed layers. The use of a multi-stage shallow fluidized bed can keep the fluidized bed at a high fluidization quality, and it is not easy to have an abnormal fluidization state that often occurs in a deep fluidized bed. At the same time, it can also effectively suppress the back mixing of solid phase particles while maintaining the overall good fluidization quality of the reactor body, so as to ensure that most of the reaction particles can have sufficient reaction time. Combined with the inter-stage temperature control, it can also form a good temperature and conversion rate gradient distribution between the stages of the reactor body, greatly improving the control level of the product quality of the generated products in the production process; the multi-stage reactor can also effectively control the concentration of the reaction gas in the tail gas and reduce the consumption of the reaction gas, which not only solves the problem of a large amount of tail gas that needs to be treated in the process, but also effectively reduces the production cost caused by the consumption of the reaction gas; an overflow pipe is arranged between two adjacent fluidized bed layers, and the particles between the various bed layers can be continuously and stably transported, which is conducive to ensuring the stability of the production of the device and the long-term safety and reliability of the equipment.
[0010] Among them, the inlet of each overflow pipe is arranged at the plane where the material surface of the fluidized bed layer of the first level is located, and the outlet of each overflow pipe is arranged below the material surface of the fluidized bed layer of the next level and is located between the material surface of the next level and the gas distribution plate.
[0011] The overflow pipe is a hollow cylindrical pipe with a diameter ranging from 25 to 35 mm. Each overflow pipe penetrates the fluidized bed layer of the first level, and the gas distribution plate is arranged between two adjacent fluidized bed layers.
[0012] Wherein, heat exchange tube bundles are arranged inside the N-stage fluidized bed layers, and both ends of each heat exchange tube bundle are fixed on the cylinder wall of the reactor body.
[0013] Wherein, a gas inlet is arranged at the bottom end of the reactor body, a gas outlet is arranged at the top end of the reactor body, and a filter is arranged at the gas outlet.
[0014] Wherein, a generated product powder outlet is provided near the Nth stage fluidized bed layer, one end of the generated product powder outlet is connected to a storage tank, and the other end is connected to the cylinder wall of the reactor body.
[0015] Among them, an inert gas supplement inlet is arranged on the side wall of the reactor body on the second to N-1th fluidized bed layers at a position higher than the inlet of the overflow pipe.
[0016] A feeding device is provided on one side of the first-stage fluidized bed layer, and the feeding device comprises a feeding hopper and a screw feeder. One end of the screw feeder is connected to the bottom end of the feeding hopper, and the other end is connected to the reactor body.
[0017] The inlet of the overflow pipe is set at the plane position of the material surface of the fluidized bed layer of the first level, and then the outlet of the overflow pipe is set below the material surface of the fluidized bed layer of the next level, and the position of the overflow pipe is set at a certain height from the gas distribution plate of the next level, so that the particles can smoothly overflow from the inlet of the overflow pipe and then overflow from the outlet of the overflow pipe; the hollow cylindrical overflow pipe with appropriate diameter can maintain a certain material level height and automatically adjust the overflow pipe material level height according to the pressure drop of the adjacent two-level bed layers. The overflow pipe is set between the adjacent two-level fluidized bed layers, so that the raw materials can gradually overflow to the next-level fluidized bed layer and react with the reaction gas; heat exchange tube bundles are set in each reactor, The heat exchange tube bundles are heat supplementary tube bundles and heat extraction tube bundles. The heat supplementary tube bundles are mainly used to heat the uppermost several levels of beds so that the reaction particles entering the reactor can reach a suitable reaction temperature as soon as possible. The heat extraction tube bundles are mainly arranged in the bottom reactors at each level to prevent the particle materials from sintering due to the release of reaction heat and causing the particles to lose fluidization, thereby causing the bed to lose fluidization; a generated product powder outlet is arranged near the Nth level fluidized bed, and then the generated product powder outlet is connected to the storage tank, and the generated product can be sent to the storage tank through the generated product powder outlet for storage; an inert gas supplementary inlet is adopted, and inert gas can be supplemented at the inert gas supplementary inlet to ensure that the upper levels of the bed have good fluidization quality.
[0018] The number of multi-stage fluidized beds can be increased or decreased according to the conversion rate requirements of the multi-stage hydrofluorination or reduction process.
[0019] Beneficial effects:
[0020] The beneficial effects produced by adopting the technical solution of the utility model are as follows:
[0021] (1) A plurality of gas distribution plates are arranged inside the reactor body, and the plurality of gas distribution plates divide the reactor body from top to bottom into N fluidized bed layers. The use of a multi-stage shallow fluidized bed can make it easier for the shallow fluidized bed to maintain a high fluidization quality, and it is not easy to have an abnormal fluidization state that often occurs in a deep fluidized bed. At the same time, it can also effectively suppress the back mixing of solid phase particles under the premise of maintaining the overall good fluidization quality of the reactor body, so as to ensure that most of the reaction particles can have sufficient reaction time. Combined with the inter-stage temperature control, it can also form a good temperature and conversion rate gradient distribution between the stages of the reactor body, greatly improving the control level of the product quality of the generated products in the production process; the multi-stage reactor can also effectively control the concentration of the reaction gas in the tail gas and reduce the consumption of the reaction gas, which not only solves the problem of a large amount of tail gas that needs to be treated in the dry uranium conversion process, but also effectively reduces the production cost caused by the consumption of the reaction gas; an overflow pipe is arranged between two adjacent fluidized bed layers, and the particles between the beds can be continuously and stably transported, which is conducive to ensuring the stability of the production of the device and the long-term safety and reliability of the equipment.
[0022] (2) The inlet of the overflow pipe is set at the plane position of the material surface of the fluidized bed layer of the first level, and then the outlet of the overflow pipe is set below the material surface of the fluidized bed layer of the next level, and the position of the overflow pipe is set at a certain height from the gas distribution plate of the next level, so that the particles can smoothly overflow from the inlet of the overflow pipe and then overflow from the outlet of the overflow pipe; a hollow cylindrical overflow pipe with an appropriate diameter can be used to maintain a certain material level height and automatically adjust the overflow pipe material level height according to the pressure drop of the adjacent two-level bed layers. The overflow pipe is set between the adjacent two-level fluidized bed layers, so that the raw materials can gradually overflow to the next-level fluidized bed layer and react with the reaction gas; a heat exchange tube bundle is set in each reactor The heat exchange tube bundles are heat supplement bundles and heat extraction bundles. The heat supplement bundles are mainly used to heat the top several levels of beds so that the reaction particles entering the reactor can reach a suitable reaction temperature as soon as possible. The heat extraction bundles are mainly arranged in the bottom reactors to avoid sintering of particles due to too fast temperature rise of the particle material due to the release of reaction heat, thereby causing the bed to lose fluidization; a generated product powder outlet is arranged near the Nth level fluidized bed, and then the generated product powder outlet is connected to the storage tank, and the generated product can be sent to the storage tank through the generated product powder outlet for storage; an inert gas supplement inlet is adopted, and inert gas can be supplemented at the inert gas supplement inlet to ensure that the upper levels of the bed have good fluidization quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the technical solution of the implementation mode of the utility model, the drawings required for use in the implementation mode will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.
[0024] Figure 1 It is a structural diagram of a multi-stage uranium conversion fluidized bed reactor;
[0025] In the figure: 1. Reactor body; 2. First-stage fluidized bed; 3. Nth-stage fluidized bed; 4. Gas distribution plate; 5. Overflow pipe; 6. Heat exchange tube bundle; 7. Gas inlet; 8. Gas outlet; 9. Filter; 10. Product powder outlet; 11. Storage tank; 12. Inert gas supplement inlet; 13. Feed hopper; 14. Screw feeder. DETAILED DESCRIPTION
[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the utility model clearer, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the utility model for which protection is sought, but merely represents the selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.
[0027] This embodiment adopts a multi-stage shallow fluidized bed, which can keep the fluidized bed at a high fluidization quality. An overflow pipe is set between two adjacent fluidized bed layers, and particles between each bed layer can be transported continuously and stably, which is conducive to ensuring the stability of the device production and the long-term safety and reliability of the equipment. The specific technical solution is as follows:
[0028] like Figure 1 As shown, a multi-stage uranium conversion fluidized bed reactor comprises a reactor body 1, wherein the reactor body 1 comprises N-stage fluidized bed layers, N≥2, N is an integer, and from top to bottom are a first-stage fluidized bed layer 2 to an N-stage fluidized bed layer 3, and a gas distribution plate 4 is arranged at the bottom of each of the N-stage fluidized bed layers, the gas distribution plate 4 separates two adjacent stages of the fluidized bed layers, an overflow pipe 5 is arranged between the two adjacent stages of the fluidized bed layers, and the overflow pipe 5 passes through the gas distribution plate 4 to connect the two adjacent stages of the fluidized bed layers.
[0029] A plurality of gas distribution plates 4 are arranged inside the reactor body 1, and the plurality of gas distribution plates 4 divide the reactor body 1 from top to bottom into N-level fluidized bed layers. The use of a multi-stage shallow fluidized bed can keep the fluidized bed at a high fluidization quality, and is not prone to abnormal fluidization states that often occur in deep fluidized beds. At the same time, the back-mixing of solid phase particles can be effectively suppressed while maintaining the overall good fluidization quality of the reactor body, so as to ensure that most of the reaction particles have sufficient reaction time. Combined with the inter-stage temperature control, a good temperature and conversion rate gradient distribution can be formed between the stages of the reactor body 1, which greatly improves the control level of the product quality of the generated products in the production process. The multi-stage reactor can also effectively control the concentration of the reaction gas in the tail gas and reduce the consumption of the reaction gas, which not only solves the problem of a large amount of tail gas that needs to be treated in the uranium conversion process, but also effectively reduces the production cost caused by the consumption of the reaction gas. An overflow pipe 5 is arranged between two adjacent fluidized bed layers, and the particles between the beds can be continuously and stably transported, which is conducive to ensuring the stability of the production of the device and the long-term safety and reliability of the equipment.
[0030] In this embodiment, the inlet of each overflow pipe 5 is arranged at the plane where the material surface of the fluidized bed layer of the first level is located, and the outlet of each overflow pipe 5 is arranged below the material surface of the fluidized bed layer of the next level, and is located between the material surface of the next level and the gas distribution plate 4.
[0031] The inlet of the overflow pipe 5 is set at the plane position of the material surface of the fluidized bed layer of the first level, and then the outlet of the overflow pipe 5 is set below the material surface of the fluidized bed layer of the next level, and the position where it is set is at a certain height from the gas distribution plate 4 of the next level, so that the particles can smoothly overflow in from the inlet of the overflow pipe 5, and then overflow out from the outlet of the overflow pipe 5.
[0032] In this embodiment, the overflow pipe 5 is a hollow cylindrical pipe with a diameter ranging from 25 to 35 mm. Each overflow pipe 5 penetrates the gas distribution plate 4 of the fluidized bed layer of the level where it is located and is arranged between two adjacent fluidized beds.
[0033] By using a hollow cylindrical overflow pipe 5 of appropriate diameter, a certain material level height can be maintained and the overflow pipe material level height can be automatically adjusted according to the pressure drop of two adjacent bed layers. The overflow pipe 5 is set between two adjacent fluidized bed layers, so that the raw material can gradually overflow to the next fluidized bed layer and react with the reaction gas.
[0034] In this embodiment, heat exchange tube bundles 6 are disposed inside the N-stage fluidized bed layers, and both ends of each heat exchange tube bundle 6 are fixed to the reactor body 1 .
[0035] Heat exchange tube bundles 6 are arranged in each stage of the reactor. The heat exchange tube bundles 6 are heat supplementary tube bundles and heat extraction tube bundles. The heat supplementary tube bundles are mainly used to heat the uppermost bed layers so that the reaction particles entering the reactor can reach a suitable reaction temperature as soon as possible. The heat extraction tube bundles are mainly arranged in the bottom reactors to avoid sintering of particles due to excessively rapid temperature rise of the particle material due to the release of reaction heat, thereby causing the bed layer to lose fluidization.
[0036] In this embodiment, a gas inlet 7 is disposed at the bottom end of the reactor body 1 , a gas outlet 8 is disposed at the top end of the reactor body 1 , and a filter 9 is disposed at the gas outlet 8 .
[0037] A gas inlet 7 is provided at the bottom end of the reactor body 1 and a gas outlet 8 is provided at the top end of the reactor body 1, so that the reaction gas and the inert gas can be supplied into the reactor body 1 from the gas inlet 7 and then discharged and recovered from the gas outlet 8. A filter 9 is provided at the gas outlet 8 to effectively filter the solid particles when the gas drives the particles to flow upward.
[0038] In this embodiment, a generated product powder outlet 10 is provided near the Nth stage fluidized bed layer 3 , one end of the generated product powder outlet 10 is connected to a storage tank 11 , and the other end is connected to the cylinder wall of the reactor body 1 .
[0039] A generated product powder outlet 10 is arranged near the Nth stage fluidized bed layer 3, and then the generated product powder outlet 10 is connected to a storage tank 11, so that the generated product can be sent to the storage tank 11 through the generated product powder outlet 10 for storage.
[0040] In this embodiment, an inert gas supplementary inlet 12 is provided on the side wall of the reactor body 1 at a position higher than the inlet of the overflow pipe 5 on the second to N-1th fluidized bed layers.
[0041] By using the inert gas supplement inlet 12, inert gas can be supplemented at the inert gas supplement inlet 12 to ensure that the upper beds of various levels have good fluidization quality.
[0042] In this embodiment, a feeding device is provided on one side of the first-stage fluidized bed layer 2 , and the feeding device includes a feeding hopper 13 and a screw feeder 14 , one end of the screw feeder 14 is connected to the bottom end of the feeding hopper 13 , and the other end is connected to the reactor body 1 .
[0043] A feeding device is arranged beside the reactor body 1 , so that the raw materials are fed from the feed hopper 13 and then enter the reactor body 1 through the screw feeder 14 .
[0044] The above-mentioned multi-stage uranium conversion fluidized bed reactor can be applied to a multi-stage uranium trioxide hydrogen reduction fluidized bed reactor or a multi-stage uranium dioxide hydrofluorination fluidized bed reactor. The above-mentioned reaction particles refer to U3O8 or UO2, the reaction gas refers to H2 or HF, and the generated product refers to UO2 or UF4.
[0045] Working principle of a multi-stage uranium conversion fluidized bed reactor:
[0046] Add product-grade powder into the feed hopper, add the product-grade powder into the first-stage fluidized bed in the reactor body through a screw feeder, first introduce a certain flow of N2 into the reactor at the gas inlet, and then allow the product-grade powder to enter the next-stage fluidized bed through overflow pipes at each level in an overflow outflow and flood inflow in and out manner. After the product-grade powder fills the fluidized beds at each level, add reaction raw materials into the feed hopper and switch N2 to reaction gas. The reaction gas is supplied from the gas inlet at the bottom of the multi-stage fluidized bed reactor, enters the reactor after passing through the gas distribution plate, and makes the gas evenly diffused into the multi-stage fluidized bed reactor, countercurrently contact and react with the reaction raw materials of each stage of the fluidized bed, and finally is filtered through a filter and discharged through a gas outlet for recovery. The gas outlet mainly discharges water vapor and N2 generated after the reaction. By adjusting the reaction gas flow rate and the reaction raw material feed amount, the reaction gas and the reaction raw material can be achieved. The continuous reaction of the raw materials can generate reaction product powder, which is then discharged through the reaction product powder outlet and stored in a storage tank. Since the hydrofluorination reaction is a reaction in which the gas volume gradually decreases, in order to maintain the fluidization quality of the bed, the inert gas N2 can be appropriately supplemented at the inert gas supplement inlet to ensure that the upper beds at all levels have good fluidization quality. Since the hydrofluorination reaction is an exothermic reaction, the temperature of the solid particles will gradually increase with the increasing depth of the reaction. Therefore, heat exchange tube bundles are arranged in each reactor, wherein the heat exchange tube bundles are heat supplementary tube bundles and heat extraction tube bundles. The purpose of the heat supplementary tube bundles is mainly to heat the uppermost beds so that the reaction particles entering the reactor can reach a suitable reaction temperature as soon as possible. The heat extraction tube bundles are mainly arranged in the bottom reactors at all levels to prevent the particles from sintering due to the release of reaction heat and the temperature rises too fast, thereby causing the bed to lose fluidization.
[0047] The above description is only the preferred implementation of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. A multi-stage uranium conversion fluidized bed reactor, characterized in that: The invention comprises a reactor body (1), wherein the reactor body (1) comprises N-stage fluidized bed layers, where N≥2, N is an integer, and from top to bottom are the first-stage fluidized bed layer (2) to the N-stage fluidized bed layer (3), and the bottoms of the N-stage fluidized bed layers are all provided with a gas distribution plate (4), and the gas distribution plate (4) separates two adjacent stages of the fluidized bed layers, and an overflow pipe (5) is provided between the two adjacent stages of the fluidized bed layers, and the overflow pipe (5) passes through the gas distribution plate (4) to connect the two adjacent stages of the fluidized bed layers.
2. A multi-stage uranium conversion fluidized bed reactor according to claim 1, characterized in that: The inlet of each overflow pipe (5) is arranged at the position of the plane where the material surface of the fluidized bed layer of the first level is located, and the outlet of each overflow pipe (5) is arranged below the material surface of the fluidized bed layer of the next level and is located between the material surface of the next level and the gas distribution plate (4).
3. A multi-stage uranium conversion fluidized bed reactor according to claim 2, characterized in that: The overflow pipe (5) is a hollow cylindrical pipe with a diameter ranging from 25 to 35 mm. Each overflow pipe (5) penetrates the gas distribution plate (4) of the fluidized bed layer of the first level where it is located and is arranged between two adjacent fluidized bed layers.
4. The multi-stage uranium conversion fluidized bed reactor according to claim 1, characterized in that: Heat exchange tube bundles (6) are arranged inside the N-stage fluidized bed layers, and both ends of each heat exchange tube bundle (6) are fixed on the cylinder wall of the reactor body (1).
5. The multi-stage uranium conversion fluidized bed reactor according to claim 1, characterized in that: A gas inlet (7) is provided at the bottom end of the reactor body (1), a gas outlet (8) is provided at the top end of the reactor body (1), and a filter (9) is provided at the gas outlet (8).
6. The multi-stage uranium conversion fluidized bed reactor according to claim 1, characterized in that: A generated product powder outlet (10) is provided near the Nth stage fluidized bed layer (3), one end of the generated product powder outlet (10) is connected to a storage tank (11), and the other end is connected to the cylinder wall of the reactor body (1).
7. The multi-stage uranium conversion fluidized bed reactor according to claim 1, characterized in that: An inert gas supplement inlet (12) is provided on the side wall of the reactor body (1) on the second to N-1th fluidized bed layers at a position higher than the inlet of the overflow pipe (5).
8. The multi-stage uranium conversion fluidized bed reactor according to claim 1, characterized in that: A feeding device is provided on one side of the first-stage fluidized bed layer (2), and the feeding device comprises a feeding hopper (13) and a screw feeder (14), one end of the screw feeder (14) is connected to the bottom end of the feeding hopper (13), and the other end is connected to the reactor body (1).
9. The multi-stage uranium conversion fluidized bed reactor according to claim 1, characterized in that: The number of multi-stage fluidized bed stages can be increased or decreased according to the reaction conversion rate requirements and tail gas emission concentration requirements.